CMP 101 Set 14 Programming in C

8/4/2019 CMP 101 Set 14 Programming in C

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CMP 101 Fundamentals of

Computer and programming in CProgramming in C

Textbook: E. Balagurusamy, Programming in

ANSI C, Third Edition, Tata McGraw-HillPublishing company Limited, 2004


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Programming in C

History of C

Importance of C

Structure of C Programs

Character Set, tokens,

key words & identifiers.

Data Types

Constants

Symbolic class

Variables Declarations

Variables

A variable as a constant

A variable as volatile

Storage class

Data overflow &

underflow

Already covered

Self study

Self study


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Character Set, tokens, key words &

identifiers.

Character Set Letters (Uppercase A-Z, Lowercase a-z)

Digits 0-9

Special charactersComma

Period

Semicolon

Colon

Question mark

Apostrophe

Quotation mark

Exclamation mark

Vertical bar

Slash

Backlash

Tilde

Under score

Dollar

,

.

;

:

?

!

|

/

\

~

_

$

Percent sign

Caret

Asterisks

Minus sign

Plus sign

Less than

Greater than

Left parenthesis

Right parenthesis

Left brace

Right brace

Number sign

Left bracket

Right bracket

%

^

*

-

+

(

)

{

}

#

[

]

Equal

WHITE SPACES

Blank space

Horizontal tab

Carriage Return

New line

Form feed

=


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Tokens

Keywords

Constants Strings

Operators

Identifiers Special symbols

Words with fixed meaning. Must be written in lower case.

Example: main, int, float

Variable names symbolizing memory addresses.

Rules for creating identifiers1. The first character must be an alphabet or underscore.

2. Must consists of letters, digits, or underscore

3. May have 256 characters but only the first 31 characters areimportant

4. Should be a keyword

5. Should contain white spaces

Numeric constants like -59.67Character constants like Year 2010 Year 2010

*. +. . -. (.

+, -, *,

/,


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Tokens

key words or reserve words (Prepare a list of

ANSI C Key words)

Constants

Numeric Character

Integer Real Single String

Decimal, Octal andHexadecimal

Backslash

\a bell sound

\f backspace

\n new line

\t horizontal tab

..


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Example

#include

void main

{

printf (Integer values \n\n);

printf (%d %d %d \n, 32767, 327671, 326710);

printf (\n);

}

Integer Values

3276 -32768 -32759

Output

Why negative?


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Data Types

Primary DataTypes

integer

floating

Pointsigned unsigned

Character

Int

short int

long int

unsigned int

unsigned short int

unsigned long int

float

Double

Long double

Signed

-128 to 127

Unsigned

0 to 255

Exercise: Find the size and range of each data type

void


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Variable Declaration

Data Type Keyword Declaration in C

Character (8 bits) char char a, b, c;

Unsigned Character unsigned char unsigned char a, b, c;

Signed Character signed char signed char a, b, c;

Integer (16 bits) int int x, y, z;Short Integer (8 bits) short int short int x, y, z;

Long Integer (32 bits) long int long int x, y, z;

Real (32 bits) float Float x,y,z;

Real (64 bits) double double x, y, z;

Real (89 bits) long double Long double x, y, z;


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Example

# include float x, y;int code;short int count;

long int amount;double deviation;unsigned n;char c;

/*--------------------*/

Main (){

}

x: 4 Bytes

y; 4 Bytes

code; 2 Byte

count; 1 Bytes

amount; 4 Bytes

deviation; 8 Bytes

n; 2 Bytes

c; 1 Byte

Data Segment


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User defined Data types

typedef

User can define type using typedef feature.

Example

typedef int unit;

typedeffloat marks;

Unit symbolizes int and marks float.unitx, y, z; means x, y and z are integer type.

float a, b, c; means a, b, and c are float type.


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User defined data type

enum (enumerated type)

enum identifier ( value1, value2, , valuen)

ExampleDefinition

enum day(Monday, Tuesday, Wednesday, Thursday, Friday, Saturday,

Sunday);

Variable Declaration

enum day week_st, week_end;These declaration day week_st and week_end can take values in (Monday to

Sunday) and we can use them as

week_st = Monday;

week_end=Friday;


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Storage Class

Location and visibility of variables.

# include float x, y;

void main ()

{int i;float b;-- - -functionx ();

}float functionx ();{int i;float s;

}

y

bi

si

xGlobal

x, y are visible toMain and functionx

Local to main

The variables i and b are

visible to main onlyLocal functionxThe variables i and s are

visible to functionx only

Data segment


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Storage class and their meaning

auto : known within the function it is

declared.

static: a local variable that retains its velue

even after the control is transferred to calling

program.

extern: global variable known to all functions.

register: a local variable that is stored in a

register.


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Assigning values to variables

Assignment statement

Assignment statement is defined as

identifier= expression where expression give a value.

Example

fee = 20.5;

rent = 56;

expense = fee + rent;


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Programing example

# include

void main()

{

float x, p;

double y, q;

unsigned k;

int m=54321;

long int n=1234567890;

x = 1.2345678900;

y= 9.87654321;

k= 54321;

P=q=1.0;

printf( m = %d \n, m);printf( n = %ld \n, n);

printf( x = %.121f\n, x);

printf( x = %f\n, x);

printf( y = %.121f\n, y);

printf( y = %f\n, y);

printf( k = %u p = %f q = %.121f\n, k,p,q);

}


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Defining Synbolic Constants

#define directives

#define PI 3.14

#define PASS_MARK 50

#define MAX = 100

#define STRENGTH 200

CMP 101 Set 14 Programming in C

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